Answer:
0.0000076 grams
Explanation:
We're given the half life of Tritium to be 12.3 years. In order to find out the amount of substabce remaining:
Let's first find how many 'half lives' are in 250 years.

Now what is half life? It means the time taken for a given quantity of an element to lose half it's mass.
So in 12.3 years we can find that The amount of 250 g of Tritium will be 250/2 = 125 g. In 24.6 years we'll have 125/2 = 62.5 g
So now we can devise a formula:

Where m is the remaining amount and n is th number of half lives in the time given.
Using this formula we can calculate:

Doing this calculation we get:

As we can see a very small value remains.
Vf=(35.0)+(-9.8)(2)
the answer would be 15.4 m/s
Answer:
12.46 joules
Explanation:
The formula of potential energy is:

where m is mass, g is gravitational force (9.8 m/s^2) and h is height.
- Mass is given to be 2.3 grams.
- Gravitational Force is defined as 9.8 m/s^2.
- Height is given as 553 meters.
However, mass must be in kilograms (kg) unit so we will be converting the gram to kilogram:
We know that a gram equals to 0.001 kg so 2.3 grams will equal to 2.3 * 0.001 = 0.0023 kg.
Therefore, substitute known information in the formula of potential energy:

Therefore, the potential energy is 12.46 joules.